Except for draft beer, all other beverages have readily conformed to standard dispensing equipment. The unique qualities and ideosyncracies of draft beer have created dispensing problems which have created havoc to all automatic dispensing units based upon a preset time of flow, thereby negating the control and accounting process they were intended to perform. These dispensers were required to rely on separate systems for controlling the carbon dioxide (CO.sub.2) pressure which had to be constant, and the temperature which had to be controlled within a narrow range. For these dispenser control systems to operate properly, the operator had to be on guard constantly to monitor and adjust any variations in pressure and temperature. Failure to correct these associated systems resulted in substantial waste, underfills and overfills.
The waste stems from the fact that draft beer contains active bacteria which create CO.sub.2. The beer becomes supersaturated with the CO.sub.2 and easily "fractures" to produce beer foam. Very close parameters of temperature and pressure must be maintained to control excessive foaming and waste.
The prior art metering and measuring dispensers did not have the capability to recognize and specify variances in the associated systems that directly influenced their proper functioning. As a result the associated system became so far out of proper dispensing parameters that waste could not be prevented. Because, it took more testing to fine tune the system back into balance and normal operation additional waste occurred.
A prior art beer dispensing system included a tap for automatically dispensing either the exact quantity of beer necessary to fill a glass or the exact quantity to fill a pitcher. The exact quantity was a function of time. The time for filling a glass or pitcher was set by turning the glass or pitcher selection button to set and adjust potentiometers (resistors) of RC timing circuits. Thus, if during service the selection button is turned or if the pressure changes the exact quantity was either an underfill or an overfill.
A computer was provided to record each dispensing operation of the tap. The tap comprised a modified Perlick valve, and a bell crank coupled to the actuating lever of the valve, and a solenoid for operating the bell crank to open the valve. An electronic timing circuit was provided for energizing the solenoid for predetermined periods of time for dispensing the desired quantities of beer. An add-a-head lever was provided for manually opening the valve a slight amount and thereby dispense foam for reforming a beer head. Those persons skilled in the art desiring further information for this prior art system are referred to U.S. Pat. No. 3,718,232, issued Feb. 27, 1973, to John J. Nordhoff, for a "Beer Dispensing System."
A major difference between the present invention and the prior art is the present invention in a first embodiment monitors, respectively, either the changes in pressure of the flow rate or the velocity of the beer and adjusts the on time of the dispenser accordingly to provide the exact amount of beer to fill the glass, mug, or pitcher, thereby preventing under/over fills. The dispensing system further includes pressure and temperature monitors for monitoring the beer pressure and temperature at the tap.
Another major difference is the present invention of the first embodiment is capable of monitoring associated systems, including the temperature of the beer and the CO.sub.2 pressure and provide visible warnings.
A further major difference is the present invention of the first embodiment provides in a single housing a computerized beer dispensing system which features:
A lighted annunciator panel for displaying functions on two sides.
A function select key for recalling all operating modes in memory.
A repeat pour key for use during peak business periods in which a short delay is provided between pours.
An error cancel key for computing all errors and time on during the errors.
A glass function key for drawing a glass of beer (foam).
A mug function key for drawing a mug of beer.
A pitcher function key for drawing a pitcher of beer.
A control-a-head key for head replacement made necessary by any hostess delay.
A keyed off/on/purge switch which permits purging while maintaining the memory intact.
In a second embodiment, the major difference between the present invention and the prior art is that during the programming mode the time it actually takes to fill a container is counted and the count programmed into a microprocessor; thereafter the volume count may be incrementally changed during either the operating or programming mode to adjust the quantity up or down as required to dispense the desired quantity. In this embodiment the pressure and temperature monitoring function can be either retained or deleted from the program.
In a third embodiment, the present invention differs from the prior art in that the beer dispenser is initialized by a push button switch, but entry for operation is made using a code. The public relation message capability has been omitted to reduce the display size, the initial time count to fill a selected container is used with a subsequent adjustment technique to maintain dispensing the selected quantity, and retention of the temperature and pressure monitoring function is optional.